LRTI Flashcards
host interventions that can increase likelihood of infection
smoking
alcohol
altered level of consciousness
endotracheal tube
host disease states increasing risk of infection
immunosupression
diabetes
asplenia
elderly
pathogen mediated ways infections can happen
surface adhesions
pili
exotoxins
enzymes
define community acquired pneumonia
pneumonia that developed outside the hospital or within first 48 hours of hospital admission
what is the most common cause of infection related hospitalization and mortality in the US
CAP
what is the most common pathway for bacteria pneumonia
aspiration
when does aspiration happen
during sleep
disorders that impair consciousness and depress gag reflex
what are the three ways that infection can happen
aspiration
aerosolization
bloodborne
what microorganism class is the most common pathogenic organism for CAP
virus
common bacterial pathogens of CAP
strep pneumoniae
haemophilus influenza
mycoplasma pneumoniae
legionella pneumophila
chlaymydia pneumoniae
staph aureus
which bacterial organism is most common in CAP?
strep pneumo
risk factors for drug resistance to strep
< 6 years
> 65 years
prior antibiotic therapy
co-morbid conditions
close quarters
how is mycoplasma pneumoniae spread
person to person contact
mycoplasma pneumoniae symptoms
2-3 week incubation period, slow onset of symptoms
cough, fever, headache, sore throat, N/V
what may we see with imaging in someone with mycoplasma
patchy interstitial infiltrates
what are the atypical pathogens for CAP?
legionella
mycoplasma
chlamydia
how is legionella spread
aerosolization
who is at increased risk of legionella?
older males, chronic bronchitis, smokers, immunocompromsied
legionella characteristics and symptoms
multisystem involvement - high fevers, bradycardia, multi-lobar involvement, mental status change, LFT increase
staph aureus prevalence in CAP
low prevalence
risk factors for MRSA
2-14 days post flu
previous MRSA infection
previous hospitalization
previous use of IV antibiotics
what should we get if starting someone on empiric MRSA therapy?
MRSA nasal PCR - helps us rule OUT MRSA, doesn’t diagnose but tells us we don’t have
alcoholism organism risk
strep pneumo
anaerobes
klebsiella pneumonia
COPD/smoker risk pathogens
h flu, strep pneumo, moraxella, legionella
post influenza pneumonia risk pathogens
strep pneumo
staph aureus
h flu
structural lung disease risk pathogens
pseudomonas aeruginosa
staph aureus
recent antibiotic exposure risk pathogens
staph
pseudomonas
which pathogens have a slower onset of symptoms in CAP
mycoplasma
chlamydia
how might CAP symptoms be different in elderly?
no fever
decrease in functional status, weakness, mental status changes
vitals associated with CAP
fever >38
HR > 90
SBP <90
RR >20
CAP presentation on Xray bacterial
dense lobar infiltrates
consolidation
CAP presentation on XRAY viral or atypical
patchy, diffuse interstitial infiltrates
what quality of samples can we evaluate
> 25 PMNs
<10 epithelial cells
testing we should get in CAP
could get resp culture - more used in HAP
blood culture
WBC
SCr,BUN, LFTs
O2 sat
Urinary antigen tests
nasopahyngeal PCR swab
what do we use urinary antigen tests for
strep penumoniae
legionella pneumophila
(helpful in getting a positive but we don’t change therapy)
what do we use nasopharyngeal PCR swabs for
MRSA and viral tests
when do we get a respiratory culture and a blood culture?
HAP/VAP
severe CAP major criteria (1)
septic shock
mechanical ventillation
severe CAP minor criteria (3)
RR >30
multilobar infiltrates
confusion/disorientation
BUN >20
WBC < 4,000
Platelet < 100,000
temp <36
hypotension requiring fluids
procalcitonin used for what
guides duration of treatment
not useful for starting therapy
supportive measures used in CAP
humidified oxygen
bronchodilators
fluids
chest physiotherapy
empiric CAP outpatient therapy - no comorbidities
amoxicillin
doxycycline
- azithromycin if <25% resist
empiric CAP outpatient therapy - comorbidities
beta lactam + macrolide/doxy
- amox/clav
- cefpodoxime
- cefuroxime
empiric CAP inpatient therapy - non-severe (no pseudomonas or MRSA risk)
beta lactam + macrolide
- ampicillin/sulbactam
- ceftriaxone
- doxy if contraindicated
levofloxacin
moxifloxacin
empiric CAP inpatient therapy severe (no pseudomonas or MRSA risk)
beta lactam + macrolide (FQ np)
- ampicillin/sulbactan
- ceftriaxone
- doxy if contraindicated
empiric CAP MRSA risk factors
2-14 days post influenza
previous MRSA infection
previous hospitalization w use of IV antibiotics within last 90 days
empiric CAP MRSA coverage to add
linezolid
vancomycin
empiric CAP pseudomonas risk factors
previous pseudomonas inf
previous hosp and IV antibiotic use within last 90 days
empiric CAP pseudomonas coverage agents
piperacillin/tazobactam
cefepime
meropenem
are corticosteroids reccommended in CAP?
no, only if septic shock
how long should we continue CAP therapy?
5 days minimum
clinical stability factors for discontinuation of antibiotics
temp <38 for 24 hrs
HR <100
RR <24
SBP >90
O2 sat >90
baseline mental status
what is HAP and VAP
occurring > 48 hours post admission and for VAP after endotracheal intubation
pathogenesis of HAP
miro aspirations of secretions, usually 3-5 days after hospitalization and coverts to gram negative organisms
aspiration GI contents
blood source
direct inoculation via intubation
mechanical vent
presentation of HAP/VAP
new lung infiltrate or new onset of fever, purulent sputum, leukocytosis
common pathogens for HAP/VAP
pseudomonas
enteric gram negative bacilli
acinetobacter
staph aureus (MRSA
microbiology testing done in HAP/VAP
respiratory culture
blood culture
invasive respiratory culture threshold for sample
specimen brush <10^3 CFU
BAL: < 10^4
risk factors for MDR VAP
prior IV antibiotic use within 90 days
septic shock at time of dx
ARDS prior to dx
acute renal replacement therapy
> 5 days hospitalization
when to cover MRSA HAP
risk factors
ICUs where > 10% MRSA isolates
MRSA coverage treatment for HAP
linezolid
vancomycin
pseudomonas coverage treatment for HAP
piperacillin/tazobactam
meropenem
imipenem
levofloxacin
cefepime
empiric HAP - not at high risk for mortality (not on vent or septic shock)
piperacillin/tazobactam
meropenem
imipenem
levofloxacin
cefepime
one of those
PLUS MRSA (if risk)
linezolid
vanc
empiric HAP - high risk for mortality (septic shock or vent)
piperacillin/tazobactam
meropenem
imipenem
levofloxacin
cefepime
tobramycin/amikacin
2 of those in diff classes
plus vanc or linezolid
duration of therapy for HAP and VAP
7 days minimum if clinically stable
VAP - does longer therapy decrease mortality?
no, 7 days is good
